// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/flags.h"

#include <cctype>
#include <cerrno>
#include <cstdlib>
#include <sstream>

#include "src/allocation.h"
#include "src/base/functional.h"
#include "src/base/platform/platform.h"
#include "src/counters.h"
#include "src/cpu-features.h"
#include "src/memcopy.h"
#include "src/ostreams.h"
#include "src/utils.h"
#include "src/wasm/wasm-limits.h"

#include "src/objects-inl.h" // weolar

namespace v8 {
namespace internal {

// Define all of our flags.
#define FLAG_MODE_DEFINE
#include "src/flag-definitions.h" // NOLINT(build/include)

// Define all of our flags default values.
#define FLAG_MODE_DEFINE_DEFAULTS
#include "src/flag-definitions.h" // NOLINT(build/include)

    namespace {

        // This structure represents a single entry in the flag system, with a pointer
        // to the actual flag, default value, comment, etc.  This is designed to be POD
        // initialized as to avoid requiring static constructors.
        struct Flag {
            enum FlagType {
                TYPE_BOOL,
                TYPE_MAYBE_BOOL,
                TYPE_INT,
                TYPE_UINT,
                TYPE_UINT64,
                TYPE_FLOAT,
                TYPE_SIZE_T,
                TYPE_STRING,
            };

            FlagType type_; // What type of flag, bool, int, or string.
            const char* name_; // Name of the flag, ex "my_flag".
            void* valptr_; // Pointer to the global flag variable.
            const void* defptr_; // Pointer to the default value.
            const char* cmt_; // A comment about the flags purpose.
            bool owns_ptr_; // Does the flag own its string value?

            FlagType type() const { return type_; }

            const char* name() const { return name_; }

            const char* comment() const { return cmt_; }

            bool* bool_variable() const
            {
                DCHECK(type_ == TYPE_BOOL);
                return reinterpret_cast<bool*>(valptr_);
            }

            MaybeBoolFlag* maybe_bool_variable() const
            {
                DCHECK(type_ == TYPE_MAYBE_BOOL);
                return reinterpret_cast<MaybeBoolFlag*>(valptr_);
            }

            int* int_variable() const
            {
                DCHECK(type_ == TYPE_INT);
                return reinterpret_cast<int*>(valptr_);
            }

            unsigned int* uint_variable() const
            {
                DCHECK(type_ == TYPE_UINT);
                return reinterpret_cast<unsigned int*>(valptr_);
            }

            uint64_t* uint64_variable() const
            {
                DCHECK(type_ == TYPE_UINT64);
                return reinterpret_cast<uint64_t*>(valptr_);
            }

            double* float_variable() const
            {
                DCHECK(type_ == TYPE_FLOAT);
                return reinterpret_cast<double*>(valptr_);
            }

            size_t* size_t_variable() const
            {
                DCHECK(type_ == TYPE_SIZE_T);
                return reinterpret_cast<size_t*>(valptr_);
            }

            const char* string_value() const
            {
                DCHECK(type_ == TYPE_STRING);
                return *reinterpret_cast<const char**>(valptr_);
            }

            void set_string_value(const char* value, bool owns_ptr)
            {
                DCHECK(type_ == TYPE_STRING);
                const char** ptr = reinterpret_cast<const char**>(valptr_);
                if (owns_ptr_ && *ptr != nullptr)
                    DeleteArray(*ptr);
                *ptr = value;
                owns_ptr_ = owns_ptr;
            }

            bool bool_default() const
            {
                DCHECK(type_ == TYPE_BOOL);
                return *reinterpret_cast<const bool*>(defptr_);
            }

            int int_default() const
            {
                DCHECK(type_ == TYPE_INT);
                return *reinterpret_cast<const int*>(defptr_);
            }

            unsigned int uint_default() const
            {
                DCHECK(type_ == TYPE_UINT);
                return *reinterpret_cast<const unsigned int*>(defptr_);
            }

            uint64_t uint64_default() const
            {
                DCHECK(type_ == TYPE_UINT64);
                return *reinterpret_cast<const uint64_t*>(defptr_);
            }

            double float_default() const
            {
                DCHECK(type_ == TYPE_FLOAT);
                return *reinterpret_cast<const double*>(defptr_);
            }

            size_t size_t_default() const
            {
                DCHECK(type_ == TYPE_SIZE_T);
                return *reinterpret_cast<const size_t*>(defptr_);
            }

            const char* string_default() const
            {
                DCHECK(type_ == TYPE_STRING);
                return *reinterpret_cast<const char* const*>(defptr_);
            }

            // Compare this flag's current value against the default.
            bool IsDefault() const
            {
                switch (type_) {
                case TYPE_BOOL:
                    return *bool_variable() == bool_default();
                case TYPE_MAYBE_BOOL:
                    return maybe_bool_variable()->has_value == false;
                case TYPE_INT:
                    return *int_variable() == int_default();
                case TYPE_UINT:
                    return *uint_variable() == uint_default();
                case TYPE_UINT64:
                    return *uint64_variable() == uint64_default();
                case TYPE_FLOAT:
                    return *float_variable() == float_default();
                case TYPE_SIZE_T:
                    return *size_t_variable() == size_t_default();
                case TYPE_STRING: {
                    const char* str1 = string_value();
                    const char* str2 = string_default();
                    if (str2 == nullptr)
                        return str1 == nullptr;
                    if (str1 == nullptr)
                        return str2 == nullptr;
                    return strcmp(str1, str2) == 0;
                }
                }
                UNREACHABLE();
            }

            // Set a flag back to it's default value.
            void Reset()
            {
                switch (type_) {
                case TYPE_BOOL:
                    *bool_variable() = bool_default();
                    break;
                case TYPE_MAYBE_BOOL:
                    *maybe_bool_variable() = MaybeBoolFlag::Create(false, false);
                    break;
                case TYPE_INT:
                    *int_variable() = int_default();
                    break;
                case TYPE_UINT:
                    *uint_variable() = uint_default();
                    break;
                case TYPE_UINT64:
                    *uint64_variable() = uint64_default();
                    break;
                case TYPE_FLOAT:
                    *float_variable() = float_default();
                    break;
                case TYPE_SIZE_T:
                    *size_t_variable() = size_t_default();
                    break;
                case TYPE_STRING:
                    set_string_value(string_default(), false);
                    break;
                }
            }
        };

        Flag flags[] = {
#define FLAG_MODE_META
#include "src/flag-definitions.h" // NOLINT(build/include)
        };

        const size_t num_flags = sizeof(flags) / sizeof(*flags);

    } // namespace

    static const char* Type2String(Flag::FlagType type)
    {
        switch (type) {
        case Flag::TYPE_BOOL:
            return "bool";
        case Flag::TYPE_MAYBE_BOOL:
            return "maybe_bool";
        case Flag::TYPE_INT:
            return "int";
        case Flag::TYPE_UINT:
            return "uint";
        case Flag::TYPE_UINT64:
            return "uint64";
        case Flag::TYPE_FLOAT:
            return "float";
        case Flag::TYPE_SIZE_T:
            return "size_t";
        case Flag::TYPE_STRING:
            return "string";
        }
        UNREACHABLE();
    }

    std::ostream& operator<<(std::ostream& os, const Flag& flag)
    { // NOLINT
        switch (flag.type()) {
        case Flag::TYPE_BOOL:
            os << (*flag.bool_variable() ? "true" : "false");
            break;
        case Flag::TYPE_MAYBE_BOOL:
            os << (flag.maybe_bool_variable()->has_value
                    ? (flag.maybe_bool_variable()->value ? "true" : "false")
                    : "unset");
            break;
        case Flag::TYPE_INT:
            os << *flag.int_variable();
            break;
        case Flag::TYPE_UINT:
            os << *flag.uint_variable();
            break;
        case Flag::TYPE_UINT64:
            os << *flag.uint64_variable();
            break;
        case Flag::TYPE_FLOAT:
            os << *flag.float_variable();
            break;
        case Flag::TYPE_SIZE_T:
            os << *flag.size_t_variable();
            break;
        case Flag::TYPE_STRING: {
            const char* str = flag.string_value();
            os << (str ? str : "nullptr");
            break;
        }
        }
        return os;
    }

    // static
    std::vector<const char*>* FlagList::argv()
    {
        std::vector<const char*>* args = new std::vector<const char*>(8);
        for (size_t i = 0; i < num_flags; ++i) {
            Flag* f = &flags[i];
            if (!f->IsDefault()) {
                {
                    bool disabled = f->type() == Flag::TYPE_BOOL && !*f->bool_variable();
                    std::ostringstream os;
                    os << (disabled ? "--no" : "--") << f->name();
                    args->push_back(StrDup(os.str().c_str()));
                }
                if (f->type() != Flag::TYPE_BOOL) {
                    std::ostringstream os;
                    os << *f;
                    args->push_back(StrDup(os.str().c_str()));
                }
            }
        }
        return args;
    }

    inline char NormalizeChar(char ch)
    {
        return ch == '_' ? '-' : ch;
    }

    // Helper function to parse flags: Takes an argument arg and splits it into
    // a flag name and flag value (or nullptr if they are missing). negated is set
    // if the arg started with "-no" or "--no". The buffer may be used to NUL-
    // terminate the name, it must be large enough to hold any possible name.
    static void SplitArgument(const char* arg, char* buffer, int buffer_size,
        const char** name, const char** value,
        bool* negated)
    {
        *name = nullptr;
        *value = nullptr;
        *negated = false;

        if (arg != nullptr && *arg == '-') {
            // find the begin of the flag name
            arg++; // remove 1st '-'
            if (*arg == '-') {
                arg++; // remove 2nd '-'
                DCHECK_NE('\0', arg[0]); // '--' arguments are handled in the caller.
            }
            if (arg[0] == 'n' && arg[1] == 'o') {
                arg += 2; // remove "no"
                if (NormalizeChar(arg[0]) == '-')
                    arg++; // remove dash after "no".
                *negated = true;
            }
            *name = arg;

            // find the end of the flag name
            while (*arg != '\0' && *arg != '=')
                arg++;

            // get the value if any
            if (*arg == '=') {
                // make a copy so we can NUL-terminate flag name
                size_t n = arg - *name;
                CHECK(n < static_cast<size_t>(buffer_size)); // buffer is too small
                MemCopy(buffer, *name, n);
                buffer[n] = '\0';
                *name = buffer;
                // get the value
                *value = arg + 1;
            }
        }
    }

    static bool EqualNames(const char* a, const char* b)
    {
        for (int i = 0; NormalizeChar(a[i]) == NormalizeChar(b[i]); i++) {
            if (a[i] == '\0') {
                return true;
            }
        }
        return false;
    }

    static Flag* FindFlag(const char* name)
    {
        for (size_t i = 0; i < num_flags; ++i) {
            if (EqualNames(name, flags[i].name()))
                return &flags[i];
        }
        return nullptr;
    }

    template <typename T>
    bool TryParseUnsigned(Flag* flag, const char* arg, const char* value,
        char** endp, T* out_val)
    {
        // We do not use strtoul because it accepts negative numbers.
        // Rejects values >= 2**63 when T is 64 bits wide but that
        // seems like an acceptable trade-off.
        uint64_t max = static_cast<uint64_t>(std::numeric_limits<T>::max());
        errno = 0;
        int64_t val = static_cast<int64_t>(strtoll(value, endp, 10));
        if (val < 0 || static_cast<uint64_t>(val) > max || errno != 0) {
            PrintF(stderr,
                "Error: Value for flag %s of type %s is out of bounds "
                "[0-%" PRIu64 "]\n",
                arg, Type2String(flag->type()), max);
            return false;
        }
        *out_val = static_cast<T>(val);
        return true;
    }

    // static
    int FlagList::SetFlagsFromCommandLine(int* argc,
        char** argv,
        bool remove_flags)
    {
        int return_code = 0;
        // parse arguments
        for (int i = 1; i < *argc;) {
            int j = i; // j > 0
            const char* arg = argv[i++];

            // split arg into flag components
            char buffer[1 * KB];
            const char* name;
            const char* value;
            bool negated;
            SplitArgument(arg, buffer, sizeof buffer, &name, &value, &negated);

            if (name != nullptr) {
                // lookup the flag
                Flag* flag = FindFlag(name);
                if (flag == nullptr) {
                    if (remove_flags) {
                        // We don't recognize this flag but since we're removing
                        // the flags we recognize we assume that the remaining flags
                        // will be processed somewhere else so this flag might make
                        // sense there.
                        continue;
                    } else {
                        PrintF(stderr, "Error: unrecognized flag %s\n", arg);
                        return_code = j;
                        break;
                    }
                }

                // if we still need a flag value, use the next argument if available
                if (flag->type() != Flag::TYPE_BOOL && flag->type() != Flag::TYPE_MAYBE_BOOL && value == nullptr) {
                    if (i < *argc) {
                        value = argv[i++];
                    }
                    if (!value) {
                        PrintF(stderr, "Error: missing value for flag %s of type %s\n", arg,
                            Type2String(flag->type()));
                        return_code = j;
                        break;
                    }
                }

                // set the flag
                char* endp = const_cast<char*>(""); // *endp is only read
                switch (flag->type()) {
                case Flag::TYPE_BOOL:
                    *flag->bool_variable() = !negated;
                    break;
                case Flag::TYPE_MAYBE_BOOL:
                    *flag->maybe_bool_variable() = MaybeBoolFlag::Create(true, !negated);
                    break;
                case Flag::TYPE_INT:
                    *flag->int_variable() = static_cast<int>(strtol(value, &endp, 10));
                    break;
                case Flag::TYPE_UINT:
                    if (!TryParseUnsigned(flag, arg, value, &endp,
                            flag->uint_variable())) {
                        return_code = j;
                    }
                    break;
                case Flag::TYPE_UINT64:
                    if (!TryParseUnsigned(flag, arg, value, &endp,
                            flag->uint64_variable())) {
                        return_code = j;
                    }
                    break;
                case Flag::TYPE_FLOAT:
                    *flag->float_variable() = strtod(value, &endp);
                    break;
                case Flag::TYPE_SIZE_T:
                    if (!TryParseUnsigned(flag, arg, value, &endp,
                            flag->size_t_variable())) {
                        return_code = j;
                    }
                    break;
                case Flag::TYPE_STRING:
                    flag->set_string_value(value ? StrDup(value) : nullptr, true);
                    break;
                }

                // handle errors
                bool is_bool_type = flag->type() == Flag::TYPE_BOOL || flag->type() == Flag::TYPE_MAYBE_BOOL;
                if ((is_bool_type && value != nullptr) || (!is_bool_type && negated) || *endp != '\0') {
                    // TODO(neis): TryParseUnsigned may return with {*endp == '\0'} even in
                    // an error case.
                    PrintF(stderr, "Error: illegal value for flag %s of type %s\n", arg,
                        Type2String(flag->type()));
                    if (is_bool_type) {
                        PrintF(stderr,
                            "To set or unset a boolean flag, use --flag or --no-flag.\n");
                    }
                    return_code = j;
                    break;
                }

                // remove the flag & value from the command
                if (remove_flags) {
                    while (j < i) {
                        argv[j++] = nullptr;
                    }
                }
            }
        }

        if (FLAG_help) {
            PrintHelp();
            exit(0);
        }

        if (remove_flags) {
            // shrink the argument list
            int j = 1;
            for (int i = 1; i < *argc; i++) {
                if (argv[i] != nullptr)
                    argv[j++] = argv[i];
            }
            *argc = j;
        } else if (return_code != 0) {
            if (return_code + 1 < *argc) {
                PrintF(stderr, "The remaining arguments were ignored:");
                for (int i = return_code + 1; i < *argc; ++i) {
                    PrintF(stderr, " %s", argv[i]);
                }
                PrintF(stderr, "\n");
            }
        }
        if (return_code != 0)
            PrintF(stderr, "Try --help for options\n");

        return return_code;
    }

    static char* SkipWhiteSpace(char* p)
    {
        while (*p != '\0' && isspace(*p) != 0)
            p++;
        return p;
    }

    static char* SkipBlackSpace(char* p)
    {
        while (*p != '\0' && isspace(*p) == 0)
            p++;
        return p;
    }

    // static
    int FlagList::SetFlagsFromString(const char* str, int len)
    {
        // make a 0-terminated copy of str
        ScopedVector<char> copy0(len + 1);
        MemCopy(copy0.start(), str, len);
        copy0[len] = '\0';

        // strip leading white space
        char* copy = SkipWhiteSpace(copy0.start());

        // count the number of 'arguments'
        int argc = 1; // be compatible with SetFlagsFromCommandLine()
        for (char* p = copy; *p != '\0'; argc++) {
            p = SkipBlackSpace(p);
            p = SkipWhiteSpace(p);
        }

        // allocate argument array
        ScopedVector<char*> argv(argc);

        // split the flags string into arguments
        argc = 1; // be compatible with SetFlagsFromCommandLine()
        for (char* p = copy; *p != '\0'; argc++) {
            argv[argc] = p;
            p = SkipBlackSpace(p);
            if (*p != '\0')
                *p++ = '\0'; // 0-terminate argument
            p = SkipWhiteSpace(p);
        }

        return SetFlagsFromCommandLine(&argc, argv.start(), false);
    }

    // static
    void FlagList::ResetAllFlags()
    {
        for (size_t i = 0; i < num_flags; ++i) {
            flags[i].Reset();
        }
    }

    // static
    void FlagList::PrintHelp()
    {
        CpuFeatures::Probe(false);
        CpuFeatures::PrintTarget();
        CpuFeatures::PrintFeatures();

        StdoutStream os;
        os << "Synopsis:\n"
              "  shell [options] [--shell] [<file>...]\n"
              "  d8 [options] [-e <string>] [--shell] [[--module] <file>...]\n\n"
              "  -e        execute a string in V8\n"
              "  --shell   run an interactive JavaScript shell\n"
              "  --module  execute a file as a JavaScript module\n\n"
              "Note: the --module option is implicitly enabled for *.mjs files.\n\n"
              "The following syntax for options is accepted (both '-' and '--' are "
              "ok):\n"
              "  --flag        (bool flags only)\n"
              "  --no-flag     (bool flags only)\n"
              "  --flag=value  (non-bool flags only, no spaces around '=')\n"
              "  --flag value  (non-bool flags only)\n"
              "  --            (captures all remaining args in JavaScript)\n\n"
              "Options:\n";

        for (const Flag& f : flags) {
            os << "  --";
            for (const char* c = f.name(); *c != '\0'; ++c) {
                os << NormalizeChar(*c);
            }
            os << " (" << f.comment() << ")\n"
               << "        type: " << Type2String(f.type()) << "  default: " << f
               << "\n";
        }
    }

    static uint32_t flag_hash = 0;

    void ComputeFlagListHash()
    {
        std::ostringstream modified_args_as_string;
#ifdef DEBUG
        modified_args_as_string << "debug";
#endif // DEBUG
        if (FLAG_embedded_builtins) {
            modified_args_as_string << "embedded";
        }
        for (size_t i = 0; i < num_flags; ++i) {
            Flag* current = &flags[i];
            if (current->type() == Flag::TYPE_BOOL && current->bool_variable() == &FLAG_profile_deserialization) {
                // We want to be able to flip --profile-deserialization without
                // causing the code cache to get invalidated by this hash.
                continue;
            }
            if (!current->IsDefault()) {
                modified_args_as_string << i;
                modified_args_as_string << *current;
            }
        }
        std::string args(modified_args_as_string.str());
        flag_hash = static_cast<uint32_t>(
            base::hash_range(args.c_str(), args.c_str() + args.length()));
    }

    // static
    void FlagList::EnforceFlagImplications()
    {
#define FLAG_MODE_DEFINE_IMPLICATIONS
#include "src/flag-definitions.h" // NOLINT(build/include)
#undef FLAG_MODE_DEFINE_IMPLICATIONS
        ComputeFlagListHash();
    }

    uint32_t FlagList::Hash() { return flag_hash; }
} // namespace internal
} // namespace v8
